Amid talk of a possible nuclear bomb test, North Korea vowed Tuesday to carry out a "high-intensity, all-out action."
The promise emerged from a meeting of the ruling Workers' Party and was reported by the state-run news agency KCNA.
"It emphasized the necessity to continue on with launching artificial satellites ... and long-range rockets," the agency reported.
It also said that the party leadership promised to "stage a high-intensity, all-out action, and maximize its preparation ... so that just after an order is issued, we can destroy and sweep America and the South Korean puppet army, and achieve the historic achievement of reunified Korea."
Last month, the U.N. Security Council voted to tighten sanctions on Pyongyang, after the North launched a satellite aboard a long-range rocket in December.
The North Koreans responded by announcing they planned another nuclear test and more long-range rocket launches as part of a new phase of confrontation with the United States.
Since then, U.S. officials have told CNN they believe a nuclear test could come at any time.
"I don't think there's anything special to it, except that it comes in context of renewed trash-talking from Pyongyang. But on whole it's part and parcel of their threats to engage in more provocations," a senior U.S. administration official said about Tuesday's announcement.
North Korea has conducted two previous nuclear tests, in 2006 and 2009, and proclaimed itself a "nuclear state" in 2012.
U.S. analysts believe the 2006 test had a yield of about 1 kiloton -- comparable to the explosive power of about 1,000 tons of TNT -- while the second was roughly 2 kilotons, National Intelligence Director James Clapper told a Senate committee in 2012.
By comparison, the bomb the United States dropped on Hiroshima in 1945 was roughly 15 kilotons.